Vacuum regulation.



H. C. SNOOK & E. W. KELLY.

VACUUM-REGULATION.

APPLICATION FILED OCT- 6. 1917- Patented May 28,1918

2 SHEETS-SHEET I.

H. C. SNOOK' & E. W. KELLY.

VACUUM-REGULATION.

APPLICATION FILED OCT- 6. I91?- Patented May 28,1918.

2 SHEETS-SHEET 2- I UNITED STATES PATENT orricn.

HOMER CLYDE SNOOK, OF OAK PARK, EDWIN W. KELLY, OI C HICAGO, ILLII IOIS.

vacuum REGULATION.

Specification of Letters Patent.

Patented May 28, i918.

Original application filed June 11, 1915, Serial No. 33,438. Divided and this application filed October 6,

1917. Serial No. 195,009.

To all whom it may concern: I

Be it known that we, HOMER CLYDE SNooK and EDWIN W. KELLY, citizens of the United States, of Oak Park and Chicago, State of Illinois, respectively, have invented new and useful Improvements in Vacuum Regulation, of which the following is a specification.

Our invention relates to means for regulating the degree of vacuum of an X-ray tube or other vacuum tube.

Our invention resides in osmotic-regulating means for raising and lowering the vacu- Yum of an X-ray tube or other vacuum tube -regulating means in combination with suitable system of control or electrical circuit arrangements.

inafter described and claimed.

ThlS application is a division from our application Serial Number33,433, filed June 11, 1915, which in turn is in part; a division from and continuation of our application upon which has issued Letters Patent of the United States No. 1,143,327, June 15, 1915.

For an illustration of some of the forms our invention maytake, reference is to be had to the accompanying drawings, in which;

Figurel is a longitudinal sectional view through an X-ray tube and its vacuum regulators.

Fig. 2 is a horizontal sectional view through the regulators of Fig. l with the circuit terminals slightly shifted.

Fig. 8 is a diagrammaticview of circuit arrangements suitable for the practice of our invention.

Our invention resides in the features hereouter end the tube 7 is connected, as by solcircuit arrangements suitable for the practice of our invention.

Referring to the drawings, B is the usual bulb of an X-ray tube having the glass anode stem D and the glass cathode stem E.

Within the tube are the .usual anode or target or anticathode Aand the cathode C.

In the example illustrated the head 1, of copper or other suitable material is secured to the metallic tube 2, as of steel, which fits over the tubular glass stem 3 joined to the stem D at 4. A tube 5, of copper or other suitable material, is set into the head 1 and preferably welded thereto forming a vacuum tight joint. The tube 5 extends through the stem D and at its end is welded or soldered at a vacuum tight jointsto the platinum or other tube 6 which is sealed into the end of the glass stem D forming a vacuum tight joint. corrugation 6 in the tube 6 yields, under expansion and contraction of the tube 5 due to temperature changes, and thereby prevents breakage of seal between tube 6 and glass stem D. Within the tube 5 is disposed a metallic tube 7 which at its inner end has any suitable metallic projection 8 forming electrical contact with the tube 5 or head'l. Near its which the tube 7 is suitably spaced, extract ing heat from the head 1 which conducts the heat away'from the target proper, the air then passing outwardly asindieated by the arrow through the annular space between the tubes 5 and 7 to the outer air through perforations 10 in the cap or. fer- '11 isa metallic tube 13, spaced at its inner end from the cathode G and having the projection 14: making electrical connection with the cathode C or the tube 11. The other end of the tube 13 is soldered or otherwise connected to the metallic ferrule 14, making an air tight joint therewith, the terrule 14: being secured upon the end of the outer tube or sleeve 15 of glass or any other suitable material.

aforementioned source of current with the ferrule is or the tube 13 which communicates electrically with the cathode C. llhe sleeve or tube 15 is supported upon the glass cathode stem E by the member 16, oil corlr or other suitable material, which has a plurality of longitudinally extending grooves 17 forming air passages.

lhe tube or sleeve 15 preferably termi-- nates in the bell18 which extends around the bulb B to any suitable distance.

Air or other cooling medium is introduced into the tube 13 passes therethrough and strikes the cathode C, cooling the same, and

then passes outwardly in the annular space V terior space 20is in cormnunication with the sealed in the glass and its open end com-- municate with the space 20. A conductor. 23 connec s at its one end with the tube 22 and at its other end with the platinum or its middle or equator.

between tubes 11 and 13 into the sleeve or tube 15 thence through the passages 17 over the. outsideof the cathode stem E into the bell 18 irom which it issues over the outer surface of the bulb B, all as indicated by the arrows; or in the reverse direction it tube 13 is connected to a suction pump or a partial vacuum. and we have found that the air or other medium issuing from the bell 18 clings or remains close to the bub B even beyond Sealed a the bulb n is a an. 19 whose in interior of the bulb B.- Supported' by the tube 19 is the glass bulb or vessel. 21 into which projects the tube 22 of platinum, palladium or any other suitable metal or material which is capable of operation as an osmotic member or membran The freeend of the tube 22 is closed an its. other end is other wire 2% sealed through the wall of the bulb 21. A second platinum or other suitable wire 25 is sealed in the glass wall of the Electrical connection is made" from the negative terminal of the tact/a oe bulb 21 and is connected by conductor 2% with the osmotic tube 22.

It will be noted that the bulb 21 is completely sealed against the outer atmosphere and is sealed against the interior space 20 communicating with the interior of the X- ray tube B by the osmotic member 22. In the bulb 21 is sealed an isolated charge of regulating gas for admission into the vacuum of the bulb B through the tube 22. The gas so sealed in the bulb 21 may be at atmospheric pressure when the regulator is made, or may be above or belowatmospherie pressure, but in any case it is preferably at a pressure high as compared with the pressure within the bulb B. The amountof gas or gases sealed in the bulb 21 is suffieient for a great number of regulations of the vacuum w in the bulb B, because oi the veryv great amount of regulating gas in the bulb 21 as compared with the amount in the bulb B at any time.

The gas in the bulb 21 is preferably hydrogen, though it is to be understood that any other suitable as or mixture ct gases may be employed. or example the monatomic gases such as argon, helium, neon,

zenon, etc, may be employed either singly or in combination, or In combination with hydrogen or other gas or gases.

A second osmotic tube or member 28'is sealed in the glass and has its open end in communication with the space20,'whileits outer closed end is within the bulb 29, which isopen to the atmosphereatfiu, or which may be closed or sealed and contain a gas or mixture ot gasesin which there is no gas.

of the character to be transferred from within the bulb'B through the tube 28 into the bulb 29 for raising the vacuum, or,-more genthe platinum or other wire '32 sealed in the wall of the bulb 29. Aconductor 33 connects at its one end to'the tube 28 and at its other end to the platinum or other wire3d sealed through the wall of the bulb '29;

When it is desired to lower the vacuum within the bulb B, that is, raise the gas pressure therein, the tube 22 of the lowering 2 regulator is heated by passin an electric current therethrough as tromconductors 24 and 23,v thence through the tube 22, and thence through conductors 26-and25. The

regulating gas will pass by osmosis from bulb 21 through the wall of the tube 22 to. the interior of the tube 22, thence to the" space 20 and thence into the bulb B, loweringthe vacuum, the pressure of the h drogen-or other gas within the bulb l8 eing' tube 22 being so heated, hydrogen or other 105 erally speaking, in which the concentration slight indeed as compared with the pressure within the bulb 21.

If on the other hand it is desired to raise the vacuum of the bulb B, that is, to take hydrogen or other as out of the bulb B, current is passed t ough the conductors 32 and 31 thence through the raising regulator tube 28 and thence through conductors 33 and 34 to heatthe tube 28, and there being substantially no hydrogen or other gas of the bulb B in the air or within the bulb 29 the hydrogen or other gas will come out of the bulb B by osmotic action through the tube 28 and through its wall into the bulb 29,

notwithstanding the fact that the gas pressure in the bulb 29 is very many times hi her. than the as pressure within the bulb By preference, particularly when hydrogen is used as the regulating gas, and particularly when the gas within the bulb 21 is entirely or largely hydrogen, we make the osmotic tube 22 of platinum and the osmotic tube 28 of the "raising regulator of palladium. That is, in the lowering regulator,

under the circumstances described, we prefer to use a material for the tube 22 through which the gas does not I so readily pass by osmotic action, while the tube 28 is .preferably made of a material through which the gas will very readily pass by osmotic action.

However, i11-l3l16 lowering regulator the osmotic member 22 may be made of palladium or other suitable material which passes through its wall hydrogen or other regulating gas when above a certain concentration and at ordinary temperatures. In such case We prefer to reduce the concentration of the hydrogen or other regulating gas so that when the tube 22 is at ordinary temperature it will-not pass hydrogen or other regulating gas. T6 this end the hydrogen or other regulating gas, whether confined or sealed in the bulb 21 or whether supplied from an external source, is diluted b admixture with some other gas which wi 1 not at all or with very great difliculty pass through the osmotic material 22 when at ordinary temperature and when raised to higher temperature by any electrical orv other means. Qlhus, for example, the gas in contact with or delivered to the outer wall of the tube 22 may be a mixture of substantiall ten per cent. hydrogen and ninety per cent; nitrogen, and, the tube 22 being of palladium, for example, little or no hydrogenof such concentration. will pass through its wall at ordinary or low temperature, though the reverse is true with higher concentrations. But upon raising the temperature of the material 22, the hydrogen or other regulating gas will pass therethrough into the bulb B to lowervthe vacuum. By such a combination ofmaterial for the tube 22 nd diluted gas, a relatively small amount of energy only need be expended upon the material 22 to raise its temperature to a degree to admit regulating gas promptly and in sufficient, quantity for vacuum regulation.

Furthermore, the mixture of gases, especially when confined, should be such as to be non-explosive or non-combustible when raised to the temperature to which the tube 22 is raised either by current conducted through the tube 22 as above described, or otherwise.

In Fig. 3 G is a source of alternating current, for example, a motor generator or inverted jrotary, supplying current through the rev iersing switch S and adjustable resistance R to the primary p of the transformer T having the high potential secondary s delivering current through the synchronous high potential rectifying switch F to the positive and negative high tension conductors P and N connected respectively to the anode A and cathode C of the X-ray tube. One terminal of the low tension alternating current circuit is connected by conductor 54 with one terminal of each of the transformer primaries p and 2 whose other terminals connect respectively withone terminal of the resistance r and 9" adapted to be swept over or engaged by the manually or otherwise operated switch arm 55 connected to the other conductor 56 of the low tension alternating current circuit. Associated with the primaries -p and p are the secondaries s and 8 in whose respective circuits are included @the lowering and rais mg osmotic tubes 22 and 28. Since these tubes 22 and 28 communicate with the interiorof the X-ray tube, during operationof the X-ray tube these regulator tubes assume high potentials, and consequently be tween the primaries p and p and their secondaries- 8 and s is provided high potential insulation 57.

By this arrangement the X-ray tube may be kept in operation by energy delivered by the high tension conductors P and N and while in operation the vacuum may be lowered'by bringing the switch arm 55 into engagement with resistance r whereupon the secondary s will pass current through the tube 22, the resistance of the tube 22 and.the current strength being such that a the tube 22 is raised in temperature, the temperature increasing as the amount of resistance r in'the circuit is decreased. And similarly if it is desired to raise the vacuum the switch arm 55 is brought into engagement with resistance 7- whereupon. the tube 28 is similarly heated by current derived from the secondary s A further mode of connecting the osmotic members is shown in Fig. 4, where 35 represents any suitable source of electric energy, as a storage or other battery or generator of direct current, or the secondary of a transformer for delivering alternating current. The source is connected in circuit with the adjustable resistance 36 and-the double throw switch 37. When the source 35 delivers alternating or fluctuating current the member 36 may be a resistance or a reactance or impedance. When the switch '37 is thrown over to the right it connects with contacts 38 and 39 connected respeca current strength which is again determined by the adjustable resistance 36.

Where the osmotic member is heated as above described, it itself operates as a heatdid tube. For example,

ing resistance toconvert the electrical energy into heat whose amount is determined bythe square of the current multiplied by the resistance of that part of the osmotic member through which the current flows.

In Fig. 5,8 is a secondary of a transiormer whose primary is connected in any suitable circuit, as for example, in the low tension alternating current circuit oi Fig. 3. One terminal of the secondary o is connected to the mterconnec ted tubes 22 and 28, a variable connection 58 being made with the resistance 9*, both or whose terminals are connected to the other terminal of the secondary 8 By this arrangement heating current is passed through both tubes 22 and 28 so that both are continuously admitting and extracting gas from the bulb B. By shifting the connection 58 along the resistance r one tube or the other may be heated at will to higher temperature than the other and thus secure a difi'erential regulation in that gas maybe admitted more rapidly than it isextracted or extracted more rapidly than it is admitted to thebulb B. And whatever the position of the variable connection 58 there will be in sheet a continuous stream or gas flowing into'and out of the K-ray tube, unless the'temp'eratures of the tubes 22 and 28 are'too low.

Associated with the imovable contact forming the terminal of "the conductor 58 and movable along the resistance r is the scale 59 uated'm any suitable units desig'nating degrees; of vacuum of the -ray I these units may refer to length of gap connected parallel with the Ell-ray to e. "ilfhensuita; ly adjusted or calibrated it is'poseibtltto more "the loy of. palladium and example, by osmosis, freely than platinum. By alloying Y manages contact along the resistance r opposite to any desired marking on the scale 59, and the regulators will then so be operated as to produce a degreeot vacuum or hardness of the X-ray tube corresponding with the scale reading.

It will be understood that the osmoticmemhere or membranes hereinbefore described 1 may take other than the tubular forms illustrated, any form or the osmotic member or members being comprehended within our invention, except where expressly otherwise stated. a

For any of the osmotic members hereinbetore described may be used any suitable al- 10y or osmotic'material with another osmotic material or with a materialwhich is not osmotic, or with both osmotic and non-osmotic materials.

For example, any of the osmotic members hereinbetore described may consist of an alplatinum, both plati-- num and palladium passing hydrogen, for but palladium more latinum and palladium, however, there res ts an osmotic materialwhich asses hydrogen with less facility than pails. ium alone. Such alloys may with advantage or gases and with difierent degrees of d tion of the regulating gas or ases.

While the air cooling of t e X-ray tube hereinbefore described is of advantage, it will be understood that our invention is not limited to theuseof ourherein claimed regulators in connection with an air cooled tube.

What we claim is: w p l. A regulator for the vacuum of a vacuum tube comprising an osmotic member serving as a resistance,and means for passing current through said osmotic member for heating the same.

2. A regulator for the vacuum of a vacuum tube comprising an osmotic member, and

means for passing current through said member, the resistance ofi'ered by said memtill he used with different partial pressures of the regulating bar to said current causing rise in tempera ture of said member.

3. A regulator for the vacuum or a vacuum tube comprising an osmotic member, circuit connections directly to said member at separated points thereof, and means for passing current through said connections and said member to heat said member.

a. A regulator for the vacuum of a vacuum tube comprising an osmotic "member serving asa resistance, a bulb closed to the atmosphere and charged with gas, said member separating said gas from the interior of said tube, and means for passing out." through said member forheating the sa to allowpassage of said gas therethrough.

5. A regulator for thevacuum oil a vacu= um tube comprisingan osmotic membene its bulb closed to the atmosphere and charged with gas,

nections directly to said member at separated a points thereof, and'means for paming current through connections to said memher to heat sai member to allow passage of said gas therethrough. Y

6.- A regulator for the vacuum of a vacuum tube comprising a tube of osmotic material serving as a resistance, said tube of osmotic material opening into said vacuum tube and extending to the exterior of said vacuum tube, and means for passing current through said tube of osmotic material for raising its temperature.

7 A regulator for the vacuum of a vacuum tube comprising a tube of osmotic material serving as a resistance, a bulb closed to the .atmosphere and charged with gas, said tube of osmotic m'aterial opening into said vacuum tube and extending into said bulb and forming a wall between said bulb and the interior of said vacuum tube, and means for passing current through said tube of osmotic material to raise its temperature.

8. Means for regulating the vacuum of a vacuum tube comprising an osmotic member forming a wall of said vacuum tube, and a heating circuit including said osmotic member, a source of current and adjustable current restraining means' 9. Means for regulating the vacuum of a vacuum tube comprising an osmotic member forming a wall of said vacuum tube, a heating circuitincluding said osmotic member, a source of current and adjustable current restraining means, said circuit connected to said osmotic member at separated points thereof, the current passed through said member between said points raising the temperature thereof.

10. The combination with a vacuum tube, of vacuum raising and lowering r gulators each comprisin an osmotic mem er, connections to eac of said members at separated points thereof, a source of current, a

resistance, anda switch for connecting said source of current and resistance in circuit with said connections of eitherof said osmotic members, whereby the current passed therethrou h between said separated .connections raises the temperature thereof.

11. Means for regulating thevacuum of a vacuum tube com rising an osmotic member forming a wall of said tube, difierent gases external to said tube-in contact with said osmotic member, said member when heated adapted to all throu h of one or more-of said ases and to exclude another oar-others of sai (gases, and means for electrically heating sai member.

12. Means for regulating the vacuum. of a vacuum tube com rising an osmotic memas her forming. a w ofsaid tube, vacuum said member separating said gas. from the interior of said tube, electrical conforming a wall between said ow passage thereber, a bulb closed to the atmosphere and charged with gases only some of which are adapted to pass through said member into said tube, said member forming a Wall between said tube and bulb, and means for heatin said member.

14. v regulator for the vacuum of a vacuum tube comprising an osmotic member, a bulb closed to the atmosphere and charged with difi'erent gases, said member bulb and tube, said gases consisting of anon-explosive mixture of diflerent gases only some of which are adapted to pass through said member,

and means for heating said member.

15. A regulator for the vacuum of a vacuum tube com rising an'osmotic member, a bulb close to the atmosphere and charged with diluted hydrogen gas, said member forming a wall between said bulb and said tube, and means for heating said member.

16. A regulator for the vacuum of a vacuum tube comprisin an osmotic member, a bulb closed to t e atmosphere and charged with a non-explosive mixture of hydrogen and another gas, said member when heated adapted to pass said hydrogen and to exclude said other gas, and means for heating said member.

17. A regulator for the vacuum of a vacuum tube comprising an osmotic member, a bulb closed to the atmosphere and charged with a mixture of hydrogen and nitrogen, said member forming a wall between said bulb and said tube, and means for heating said member.

18. A regulator for the vacuum of a vacuum tube comprising an osmotic member, a bulb closed to the atmosphere and charged with hydrogen diluted with another gas, said hydrogen being present in rough said member at ordinary temperatures, and means for heating said member. 19. A regulator for the vacuum of a qklliantity insufficient to cause its passage t vacuum tube comprising a member of pal1a-- dium, a bulb closed to the atmosphere and chargedwith diluted hydrogen gas, said member forming a wall between said bulb and said tube, said hydrogen being present in quantity insufiicient to cause its passage through said palladium member at ordinary temperatures, and means for raising the temperature of said palladlum member.

20.. A reg lator for the vacuum of a .vacu tube comprising a palladium mem= her, a bulb closed to the atmosphere and charged vvithhydrogen diluted with nitrogen to a degree to prevent passage of said hydrogen through said palladium member at ordinary temperatures, and means for raising the temperature of said palladium member.

21. A regulator for the vacuum of a vacui um tube comprising a palladium member, a bulb closed to the atmosphere and charged with a mixture of hydrogen and nitrogen in approxim'atelf the roportions of ten per cent. hydrogen and ninety per cent. nitrogen,

and means for raising the temperature of said palladium member.

22. The combination with a vacuum tube, of means for regulating the vacuum thereof comprising an osmotic member, a trans former, the secondary circuit of said transformer including said osmotic member, the

resistance ofiered by said osmotic member to the current passed therethrough causing rise intemperature' of said member.

23. The combination With a vacuum tube, of means for regulating the vacuum thereof comprising an osmotic member, a transformer, the secondary cii cuit of said transformer inoludin said osmotic member, the resistance ofiere by said osmotic member to the current passed therethrough causing rise in temperature of said member, and current regulating means in the primary circuit of bit . ing

because each of said members to the current passed therethrough causing rise in tem erature, thereof, and switching means for t rowing into circuit any of said transformers.

26. The combination with a vacuum tube, of means for regulating the vacuum thereof comprising a lurality of osmotic members, transformers osmotic members, the resistance odered by each of said members to the current passed therethrough causing rise in temperature thereof, switching means for throwing into circuit any of said transformers, and means associated with each transformer for controllingthe strength'of the current delivered thereby.

27. The combination with a vacuum tube, of a source of alternating current, a step-up transformer supplied from said source of currentand delivering high potential current to said vacuum tube, and means for regulating the vacuum of said tube comprisin an osmotic member, a transformer receiving energy from said source of alternating current, said osmotic member receiving current from said transformer, the resistance en ered b said osmotic member to the current passe therethrough causing rise in temperature thereof.

28. Th combination with a vacuum tube, of a source of alternating current,'a step-u transformer receiving energy from sai source and impressing high potential current upon said vacuum tube, and means for regulating the vacuum of said tube "comprising a plurahty of osmotle members, transforming apparatus receiving energy from said source of current and delivering current to said osmotic members, the resistance ofiered by .each of said osmotic members to the current passed therethrouo'h causrise in temperature thereof, an means associated with said transforming apparatus comprising a plurality of osmotic members,

transformers fer supplying current to said osmotm members, the resistance ofiered by for determining the strengths of the currents passed through said osmotic members.

In testimonywhereof We have hereunto amazed our signatures this 2nd day of 0ctober, 191?.

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